The three bidders are:\u2022 CPB Contractors (formerly Leighton Contractors)\u2022 John Holland KBR JV \u2013 comprising John Holland Group and KBR (formerly Kellogg Brown & Root), and\u2022 Lend Lease Coleman Rail JV \u2013 comprising Lend Lease Engineering and Coleman Rail.\r\nThe early works package will deliver hundreds of millions of dollars in works to prepare key sites for the start of major construction on the project in 2018. These include the relocation and protection of underground services such as gas, sewer and water mains, the relocation of trees and other road features, and the design and construction of access shafts.\r\nShortlisted bidders will be requested to submit a formal proposal in the second quarter of 2016. A contract will be awarded in mid-2016, with construction to commence soon after.\r\nThe announcement of the shortlisted bidders follows the release of the business case for the $A 10.9bn ($US 7.8bn) project, which while still largely at the planning stage, will become Australia's single largest infrastructure project.\r\nMajor works will include the construction of two 9km rail tunnels from South Kensington to South Yarra, travelling beneath Swanston Street in the city centre and a number of other rail related projects in Melbourne.\r\nThe updated business case finds the project delivers a benefit of $A 1.10 for every dollar invested (or $A 1.50 when including wider economic benefits). The project allow an extra 39,000 passengers to be transported in the peak.Victoria has committed $A 4.5bn to the project, and is seeking a matching funding commitment. It is also exploring associated commercial developments with the private sector.